Thrombotic thrombocytopenic purpura in two patients with systemic lupus erythematosus: clinical significance of anti-platelet antibodies.

Thrombotic thrombocytopenic purpura (TTP) is a clinical syndrome of unknown etiology and has a high mortality rate due to disseminated platelet thrombi. However, the mechanism of platelet agglutination is not understood. Although an immunological mechanism has been suggested as the basis for the pathogenesis of TTP, any possible immune-mediated etiology remains unclear. The association of TTP with systemic lupus erythematosus (SLE) affords a unique opportunity to study such possibilities, because SLE is a prototype of autoimmune disease. This report describes two patients with SLE who developed TTP. The development of anti-platelet antibodies is one possible immunological mechanism for platelet agglutination in patients with SLE complicated by TTP. More importantly, patient J.Y., who had anti-platelet antibodies, responded dramatically to high doses of prednisolone.